Vegetable Oil for Lubricating Chain Saws

VEGETABLE OIL FOR LUBRICATING CHAIN SAWS

by Skip Garrett, Mechanical Engineer

IntroductionTo work properly, chainsaw chains and bars must be lubricated. In the past, most operators have used petroleum-based oils. When a chain saw is used, virtually all of the lubricant ends up in the environment. Every year thousands of gallons of chain-and-bar oil are carried into the forests and none returns.

The demand for environmentally acceptable products is growing rapidly. There is increased concern about the influence of petroleum-based oils on the envi-ronment. Also, exposure to petroleum-based oils can have adverse health effects on users. One potential alternative is the use of “environmentally compatible” or “enviro-friendly” oils that are produced from vegetables. To achieve this classification, an oil must be nontoxic and must biodegrade rapidly if spilled. Rapeseed-based (usually called canola) oil is currently the most common environmentally compatible chain-and-bar lubricant.

BackgroundVegetable-based oils are triglycerides or natural esters that come from agricultural crops. These oils are natural products and therefore their chemical composition varies somewhat from one crop to another.They have some undesirable character-istics. Their cold-temperature properties and oxidation stability are their main disadvantages compared to petroleum-based oil, and additives are needed to overcome these problems. Vegetable oils have many good natural properties including good lubricity, good resistance to shear, a high flash point, and a high viscosity index. Vegetable oils vary in price but, in general, are about twice as expensive as petroleum-based oils.

Modern vegetable-based lubricants first appeared in the marketplace in Europe in the mid-1980s. The acceptance and use of these products, particularly in the European forest industry, is widespread and growing. The two main reasons for this are concerns about workers’ occupational safety and health and environmental protection.

Petroleum-based oils are known carcinogens and medical records show that they cause discomforting eczema and oil acne. In addition, prolonged ex-posure to petroleum-based-oil mist can cause irritation of the respiratory tract. Environmental damage caused by petroleum-based oil spills has had extensive attention from the media.

The benefits of using vegetable oils are well known in Germany, where there are about 80 brands available, and in the Scandinavian countries. In Austria, all petroleum-based chain saw oils are banned. The Coordinating European Council (CEC) has established a test methodology for bio-degradability. This test standard (CEC-L-33-T-82) measures the amount of oil that biodegrades over a 21-day period. (Cautionary Note: Some products show CEC on their product labels and all this means is that the products contain some portion of bio-degradable material. They may still contain mineral oils or mineral-based additives. It is best to find out what percentage of the total product will biodegrade in 21 days.)

Readily biodegradable, petroleum-free lubricants based on canola oil—including hydraulic fluids, greases, motor oils, concrete release oils, two-cycle oils, and chainsaw-oils are now available commercially in North America. Canola oil is a renewable, sustainable farm product. Manufacturers claim that these products are rapidly bio-degradable, nontoxic to the environment, and safe for operators and mechanics.

Canola-based chain-and-bar oil has been extensively tested in Europe. It has excellent lubricating properties and some studies have shown up to 40 percent reduction in consumption without sacrificing bar-and-chain life. Most high quality or “professional” chain saws have sophisticated chain oilers that are more efficient and have the capability of controlling the amount of oil being used (figure 1). Manufacturers and some users claim that there is a potential for extended bar-and-chain life when using canola-based products because it lubricates and adheres to metal better than petroleum-based oils.

Canola-based chain oils have low vapor pressure, which reduces inhalation of fumes by users. Its composition is similar to human skin oil and this can reduce skin irritation and eczema for operators and mechanics. Tests have shown that canola-based chain oils provide good performance down to -13 degrees F but stor-age can affect the pour point temperature (they may not pour easily after standing for several days at -22 degrees F). Generally, vegetable-based oils have higher flash points than petroleum-based products.

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Figure 1—Chainsaw chains and bars must be lubricated. Virtually all of the lubricant ends up in the environment.

FERIC STUDYThe Forest Engineering Research Institute of Canada (FERIC) tested and reported on field trials of a vegetable-based oil for lubricating chain saws. (See FERIC General Field Note Number 35.) They conducted two trials, one with chain saws on a conventional manual falling operation and the other with chain saws on Rottne single- and double-grip harvesters on a shortwood mechanical harvesting operation. The climatic conditions on the two tests were different as the hand falling took place in a wet, temperate Coastal rain forest while the mechanical harvesting took place in sub-zero temperatures. Both trials used an oil called Binol that is produced in Sweden by Karlshamns AB. This chain oil is canola-based with additives, and the manufacturer claims that the product (oil and additives) is non-toxic and biodegradable (degrading 97 percent in 21 days.)

The overall results were positive. Users reported that the vegetable-based oil was easier to clean from clothes and equipment. Users also experienced less skin irritation. Rottne harvester operators noticed a significant reduction in the oil mist that collects on the machines’ windows due both to the cleanliness of the Binol compared to petroleum-based oil and to the reduced consumption of oil. The operators claimed a 60 percent reduction in consumption, however, the manufacturer does not claim such a large reduction. They also claimed that Binol increased the life of the bar-and-chain, but the hand fallers reported no noticeable change. The coldest temperature during the trial was -13 degrees F, and there were no lubrication-related failures.

The vegetable-based oil performed satisfactorily in both trials. FERIC reported that Binol costs about twice as much as mineral oil, but when taking into account the manufacturer’s claim of a 40-percent reduction in consumption, the cost increase over mineral oil is around 20 percent. FERIC noted that the potential for extended bar-and-chain life may offset this cost. The report concluded that even with the increased cost, the benefits for workers and the environment make vegetable-based oils an attractive alternative.

FOREST SERVICE FIELD TRIALA limited field trial of three vegetable-based chain oils was conducted by Winston Rall on the Wind River Ranger District of the Gifford Pinchot National Forest. Rall has a great deal of interest in and experience with chainsaws and is the lead instructor for chainsaw training and certification in Region 6 (figure 2). He tried vegetable-based products from Greenland Corporation, Green Oil Company, and Stihl, Incorporated.

Figure 2—Forest Service employee operating a chainsaw.

All of the vegetable-based oils performed adequately in these limited field trials. While these trials were by no means scientific studies, some opinions from an experienced sawyer are worth noting. Starting with a new bar and chain, Rall could see no difference in the amount of wear shown on these components (and after using one of the vegetable-based oils, he felt that the bar showed more wear than expected). He noted that the oil was difficult to see—good for esthetics and the environment, but somewhat disconcerting for the operator. Rall would not recommend using these products in a fire situation such as bucking burning logs because it appeared that the oil comes off or evaporates in extremely hot conditions (Petroleum-based oils also have problems in these conditions). Rall was pleased that he saw no oil sheen “rainbows” in puddles or rainy weather and that the oil was less noticeable following cutting operations. Rall recommends using these pro-ducts, particularly when environmental protection is important, in work such as streamside restoration, and in areas where esthetics are a concern, such as public recreation sites and hiking trails. Please bear in mind that these observations and opinions are based on very limited field trials.

CONCLUSIONThe information contained in this publication is based on background investigations, literature searches, and consultations with technical specialists. Based on this and limited field observations, vegetable-based chain-and-bar oils are an attrac-tive alternative to petroleum-based oils. The cleanliness and non-toxic characteristics of the vegetable-based oils make them worth trying. Chainsaw users that are working in environmentally-sensitive areas should use these envi-ronmentally-compatible oils instead of conventional petroleum-based chain-and-bar oil.